Female reproductive cells (gametes) are called eggs, and male reproductive cells (also gametes) are called sperm. The main difference between germ cells (eggs and sperm) from somatic (all other) cells of the body is that germ cells have a single set of chromosomes, namely 23 pieces. While in all somatic cells there are 46 of them.
This is necessary so that during fertilization (fusion of egg and sperm), the number of chromosomes remains constant and does not increase indefinitely. To mature and become capable of fertilization, eggs and sperm travel a fairly long way.